Continuous annealer



J. MYLO ETAL ATTORNEY Q N O S m E N H mOO J H a Cs M E N H on OM OJ J L llllllllllllll ll lllilllllllllllll CONTINUOUS ANNEALER Filed June 18, 1962 Dec. 8, 1964 containers.

United States Patent "cc 3,159,873 tIflN'liNUOUS ANNEALER John Mylo, Athens, and John C. this and llamas P.

Richeson, Decatur, Alan, assignors to Monsanto Company, a corporation of Delaware Filed lune 18, 1962., Ser. No. 263,246

4 Claims. (Cl. 18-1) This invention relates to an apparatus for annealing filamentary material and, more particularly, to an apparatus for heat-relaxing'or relieving the internal strains in filamentary material, for instance, textile filaments or fibers formed from synthetic material, such as acrylonitrile polymers or the like.

In the production of tow or filaments, and in particular continuous synthetic filaments of the type which may be formed from acrylonitrile polymers or the like, the freshly formed filaments produced by the spinning operation are subjected to an orientation treatment such as heat-stretching, or the like. This orientation treatment aligns the filament molecules in the direction of the filament axis and alters the physical characteristics of the filamentsin many ways, including the vital feature or" increasing the tensile strength of the filaments to the degree necessary to permit commercial use. However, this heat-stretching operation also leaves the filaments in an internally strained condition and if this strained condition is not relieved, fibrillation will result, that is, the splitting oil from the filaments of longitudinal sections or fibrils of material during the application of stress, usually in the form of abrasion.

In addition, the stretched filaments have a high residual shrinkage capacity and tend to shrink on subsequent heating at elevated temperatures. Furthermore, as a result of the stretching operation, filament extensibility is decreased, limiting its use in such textile operations as knitting and weaving where a high extensibility is desired.

It has been proposedin the past to'overcome or reduce these undesirable physical characteristics inherent in stretched filaments by heating the internally strained filaments while in a relaxed condition so that the strains are relieved. By this heat-relaxing treatment, filamentquality is materially improved as this operation reduces or substantially eliminates fibrillation and extensibility is increased. In the past, many arrangements have been proposed for subjecting filaments to this heat-relaxing or annealing treatment. For instance, it has been, suggested 3,159,873 Patented Dec. 8, 1964 ration and processing of materials so that the end product can be obtained with a minimum of operations involved and time expended. Interruption of the smooth flow in a production line, by operations where the handling of material and the expenditure of time is considerable, is costly and reduces the output below that which could otherwise be obtained.

crimped tow or filaments in the container otherwise often results in considerable filament entanglement which ren: ders removal of the annealed tow in a continuous separated form from the container a difficult operation.

In an effort to avoid the above described disadvantages of the batch type annealing process, it has been conventional to provide an apparatus consisting of an enclosure containing an atmosphere of steam into which yarntow or filaments are introduced and from which they are drawn through suitable openings in the enclosure. The openings for the passage of the filaments into and out of the enclosure are preferably as small as possible so as to minimize the escape of steam. Across these openings, there is a pressure drop and steam escaping exerts a friction effect on the filaments passing through the openings, which sets up a hard to control tension in the filaments additional to the tension deliberately induced by, for example, mechanical stretching devices. The increment of tension resulting from the pressure drop at the openings Y has an adverse eiiect on the filaments, resulting in fibrillathat annealing of filamentary material maybe accornplished by placing large batches of material in suitable The containers can then be placed in autoclaves or similar chambers so that the material can be subjected to a heating medium, such .as steam; Thus,

.produce an end product which is devoid of coloration, or

what may. be classified as a substantially white material.

. textile product.

tion, especially at the entrance opening where the flow or" steam from the enclosure is counter to the direction of travel'of the filaments thereinto. A further objection of this type of continuous annealing apparatus is that the exhaust of steam from the entry and exit portals constitutes a'definite safety hazard and also may cause undesired changes in the atmospheric conditions surrounding the area in which it is to be employed.

Accordingly, an object of this invention is to provide a new and novel apparatus for heat-relaxing or annealing internally strained filamentary material.

Another object of this invention is to provide a new and novel apparatus for annealing filamentary material, such as yarn or tow, which reduces or substantially eliminates the tendency of the filaments to discolor and is therefore capable of producing a relatively white, annealed A further object of this invention is to provide a new and novel apparatus for annealing filamentary material t is welllmown that filaments formed from acrylic materials such as acrylonitrile'polymers tend to take on a yellow hue when subjected to elevated temperatures over an extended period of time. This so-calied batch type of annealing process is not, therefore, well adapted for producing such an end product as the large :mass offilaments are necessarily cooled at. an undesirably slow rate and therefore remains in a heated state for longer periods than necessary for annealing purposes. As a result of quantities and which permits a pre-determined degree of annea1ing to be easily carried out. i,

such as'a tow of synthetic filaments, which operates in a highly efiicient, saieand continuous manner'on a continuously running length oftow.

A still further object of this invention is to provide an apparatus for annealing synthetic filamentary material, 7 which apparatus permits the rapid and continuous annealing of uncrimped filamentary tow or yarn, and which permits the tow or yarn to be packaged directly in tow form with virtually no filament entanglement.

Yet another object of thisinvention is to provide a new and improved apparatus for annealing filamentary material which mornentarily subjects successive portions of the material to a heated medium in accurately controlled A further object of this invention contemplates the provision of a new and novel'apparatus for use in continuousl y, quickly and safely annealing filamentary tow oi economydictate a smooth continuous flow in the prepaor'yarnby use of prssurized steam, which,apparatus sassevs is of such design as to permit controlled shrinkage of the tow or yarn as it is momentarily subjected to the annealing treatment.

According to the present invention, the foregoing and other objects are attained by providing a continuously operable annealing apparatus having a tapered, helical passageway through which the yarn tow is conveyed during the annealing operation. A particularly advantageous scheme for admitting steam to this passageway is provided for, steam leakage from the ends of the passageway being minimized by the creation of higher pressure air zones or curtains at such ends, the air so employed providing the additional advantage of aiding the condensation of the steam unit in the annealing operation. The result is an annealing apparatus that is continuously operable over a selectively variable speed range with a minimum of steam escaping, which apparatus, by virtue of the tapered helical passageway, effects a controlled shrinkage of the yarn tow as it is subjected to the annealing influence.

Referring now to the drawing, the continuous annealing apparatus, generally indicated by reference numeral 10, is seen to comprise a housing 12 having formed longitudinally thereof a tapered bore 14 which receives a similarly tapered rotor member 16, the rotor extending substantially throughout the length of the housing 12. The housing is preferably of substantially circular cross section and may be formed of any suitable material, such as steel, with conventional insulation, not shown, inclosing the major portions of the housing to retard heat transfer. The difference in diameters of the bore 14 and the rotor are such that, when the rotor is housed within the bore, there is defined a uniform, annular space between the wall of the bore and the surface of the rotor sufficient to accommodate the range of tow thickness one anticipates encountering. The degree of taper of the bore and rotor will be determined by the amount of shrinkage desired during the annealing operation and, for that matter, may vary along the length of the annular chamber in such fashion as is found to provide the desired results. Formed integrally with the housing and substantially throughout the length of the tapered bore, there is provided a helical ridge 18 which extends radially inwardly from the wall of the bore to a point immediately adjacent the surface of rotor 16, there preferably being a slight rubbing contact between the innermost extension of the helical ridge and the rotor. By this means it will be seen that the helical ridge 18, the surface of rotor 1d and the wall of the tapered bore 14 define a tapering, helical passageway along which the tow or yarn that is to be subjected to the annealing process may be conveyed. At

' the end of the housing defining the larger end of the tapered bore 14, there is formed an entrance slot 20 through which the tow or yarn is passed prior to being conveyed through the helical passageway, the size of the slot being no larger than necessary to accommodate the largest size tow which it is antipicated that will be handled. A similarly formed exit slot 24 is formed at the opposite end of housing 12, that is, the end adjacent the smaller diameter of bore 14, through which the tow 26 is extracted subsequent to the anneaiing operation.-

At either end of rotor 16, there is provided an integral extension of reduced diameter forming rotor mountiug shafts 28, 30 which are rotatably carried by suitable journal bearings 32. On shaft 28, there is fixably mounted a driven gear 34 which meshes with driving gear 3-5, the latter being driven by any conventional variable speed drive mechanism, not illustrated, through drive shaft 38.

Steam is admitted at selected points within the interior of the annealing apparatus by way of steam manifold which extends axially of shaft 23 and rotor 16 to communicate between steam distribution passages 42 and a source of steam, not illustrated, located exteriorily of housing 12. By this arrangement it will be noted that steam can be admitted at some intermediate point along the helical passageway 22 to percolate towards the ends thereof where it is trapped to waste. The number and location of the steam distribution passages 42 will vary with the particular installation and with the result desired to be obtained and it is only critical to the spirit of the present invention that the steam be distributed at generally intermediate points along the tapering helical passageway in such a fashion as to allow the steam to flow from such intermediate point towards the ends of the helical passageway.

The ends of housing 12 are sealed by means of cap plates 44 which may be attached in any suitable fashion, such as by welding.

The steam flowing along the tapering helical passageway 22 from the distribution passages 42 towards the ends of the passageway will tend to exhaust quite forcefully through the slots 20, 24. Another important feature of the present invention here comes into play in the form of a provision of means to effect a zone of air maintained at a pressure slightly higher than that of the steam, on the order of l to 5 lbs. p.s.i. higher, which, when employed in the present arrangement, has been found to substantially retard the escape of steam through the slots 29, 24. Such pressurized air is admitted to the helical passageway 22 adjacent the ends thereof by means of air feeder lines 46 which may be connected to a common source of controlled air pressure, the air being supplied therefrom preferably having a low moisture content. By this arrangement, there is created at the end regions of the helical passageway 22 a zone of higher pressure, relatively dry air which serves as a curtain between the helical passageway and the exterior of the housing 12.

In order to dispose of partially condensed steam traveling towards the ends of the helical passageway 22, there is provided a number of drainage lines 48 which communicate between selected points along the helical passageway 22 and a common trap 50. The location of drainage lines 43 has not been found to be critical, it being essential only that they be positioned in the vicinity of the ends of the helical passageway, the greater number being located at the end of larger passageway diameter. In this manner, when the annealer is placed in its operative position, wherein the tapered bore 14 extends substantially horizontally, the greater amount of drainage occurring at the lower region of the tapered bore will be accommodated.

It has also been found desirable to provide a steam chest 52 within housing 12 at the end of smaller taper, which steam chest communicates between a point exterior of housingv 12 and the end of the helical passageway having the smaller diameter by way of exhaust ports 54. By this means, uncondensed steam is carried off at a point upstream, relative to the direction of travel of tow 26, of the air curtain created by the admission of dry air through the uppermost feeder line 6, as viewed in the drawing.

In operation, steam is admitted through steam distribution passages 42 by way of steam manifold 40 and the annealer is allowed to come up to the desired operating temperature. At this time, pressurized air is admitted to the end regions of helical passageway 22 by way of air feeder lines 46; the annealer is now ready to receive a tow or 'yarn material. The variable speed drive mechanism is activated to drive the rotor at a suitable speed, as determined by the desired results, and the tow or yarn is fed through entrance slot 20 into the helical passageway 22, from which point it is conveyed along the length of the housing byvir tue of rotation of the rotor 16 to exit at slot 26. The steam issuin: from distribution passages 42'will percolate toward each end of the helical passageway where its condensed portions will -be drained by lines 48 and its unconv teachings.

densed portions exhausted through steam chest 52. The

' curtain of air set up by admission of air at the ends of the helical passageway 22 provide the secondary advantage of assisting in the condensation of the steam used in the annealing operation. Depending on the results desired to be obtained, the speed of travel of the tow or yarn through the helical passageway, the taper of the passageway, the heat state of the steam, the location and number of the steam distribution passages 42, and the depth of the helical passageway, as measured radially of rotor 16, may be varied by one skilled in the art of yarn annealing to effect the desired results.

Obviously, numerous modifications and variations of the present invention are possible in the light of the above It is, therefore, to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described therein.

What is claimed is; ,1. An apparatus for use in treating continuously moving filamentary material with a heated fluid, comprising an elongated, tapered rotor means, a housing having a tapered chamber shaped to receive said rotor means, the walls of said chamber being provided with a helically extending ridge; said rotor, bore and ridge defining a,

helical, filament conveying passageway, said rotor means having a longitudinal bore and radial passages formed in said rotor and interconnecting said helical passageway with said longitudinal bore, said bore communicating between said radial passages and the exterior of said housing, a source'of heated fluid communicating with said longitudinal bore, drive means drivingly connected to said rotor means, a'source of relatively dry, pressurized aircommunicating with said helical passageway at opposite ends thereof to thereby retard the escape of said heated fluid whereby, as a filamentary tow is fed through said apparatus along said helical passageway, said tow is subjected to a controlled shrinkage.

2. A continuous annealing apparatus for use in continuously treating a moving filamentary tow, comprising an elongated housing having a tapered, circular chamber extending lengthwise thereof, tapered rotor means housed within said chamber; integral, helical ridge means extending along the interior wall of said chamber radially inwardly thereof to thereby define a tapering, helical pascating with said axial bore; a plurality of radially extending ports formed adjacent both ends of said housing to communicate between points exterior said housing and points adjacent the end most regions of said helical passageway, a source of pressurized air communicating with said ports, whereby a zone of pressurized air is created at the ends of said helical passageway'to thereby retard the escape of steam thereform, the taper of said helical passageway controlling the degree of tow shrinkage.

, 3. An apparatus as defined in claim 2 and further comprising drainage ports extending radially through the Wall of said housing at either end thereof. 3

4. An annealing apparatus for use in continuously treating a moving filamentary tow, comprising an elongated housing having a tapered chamber extending lengthwise thereof, tapered rotor rneans housed within said chamber; helical ridge means extending along the interior wall of said chamber radially inwardly thereof to thereby define a tapering, helical passageway between said rotor means and said chamber, an axial bore formed in said rotor means to extend between one end and an intermediate point thereof, a plurality of axially spaced, radially extending passageways formed in said rotor means to communicate between said axial bore and said helical passagew y, whereby a fluid treating medium may be admitted to said helical passageway by way of said axial bore; a plurality of radially extending ports formed adjacent both ends of said housing to communicate between points exterior said housing and points adjacent the endmost regions of said helical passageway, whereby a zone of pressurized gas may be generated at the ends of said helical passageway upon communication of said ports with a source of pressurized gas to thereby retard the escape of a fluid medium therefrom, the taper of said helical passageway controlling the degree of tow shrinkage.

References Cited in the file of this patent UNITED STATES PATENTS 3,079,640 Kawai et a1. Mar. 5, 

1. AN APPARATUS FOR USE IN TREATING CONTINUOUSLY MOVING FILAMENTARY MATERIAL WITH A HEATED FLUID, COMPRISING AN ELONGATED, TAPERED ROTOR MEANS, A HOUSING HAVING A TAPERED CHAMBER SHAPED TO RECEIVE SAID ROTOR MEANS, THE WALLS OF SAID CHAMBER BEING PROVIDED WITH A HELICALLY EXTENDING RIDGE; SAID ROTOR, BORE AND RIDGE DEFINING A HELICAL, FILAMENT CONVEYING PASSAGEWAY, SAID ROTOR MEANS HAVING A LONGITUDINAL BORE AND RADIAL PASSAGES FORMED IN SAID ROTOR AND INTERCONNECTING SAID HELICAL PASSAGEWAY WITH SAID LONGITUDINAL BORE, SAID BORE COMMUNICATING BETWEEN SAID RADIAL PASSAGES AND THE EXTERIOR OF SAID HOUSING, A SOURCE OF HEATED FLUID COMMUNICATING WITH SAID LONGITUDINAL BORE, DRIVE MEANS DRIVINGLY CONNECTED TO SAID ROTOR MEANS, A SOURCE OF RELATIVELY DRY, PRESSURIZED AIR COMMUNICATING WITH SAID HELICAL PASSAGEWAY AT OPPOSITE ENDS THEREOF TO THEREBY RETARD THE ESCAPE OF SAID HEATED FLUID WHEREBY, AS A FILAMENTARY TOW IS FED THROUGH SAID APPARATUS ALONG SAID HELICAL PASSAGEWAY, SAID TOW IS SUBJECTED TO A CONTROLLED SHRINKAGE. 